382 Florence Peebles. 



8. Neither head nor tail region of the embryo can be taken as 

 fixed points, the growth at each end proceeds until the head and 

 tail become folded off from the blastoderm. 



9. After destruction of all of the material of the primitive streak 

 except its anterior end a small embryo with eight to ten pairs of 

 somites develops. 



10. The posterior third of the primitive streak furnishes the 

 material for the caudal region of the later embryo. The middle 

 third represents the trunk region, and the anterior third that part 

 of the embryo which lies between the heart and the tenth to 

 twelfth pairs of somites. The material of the primitive streak 

 does not enter into the formation of the brain. 



The Woman's College, 



Baltimore, June 1, 1904. 



